more stuff

1 files changed, 19 insertions, 1 deletions

diff --git a/src/util.rs b/src/util.rs
index fe11c38..a7c2d5e 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -1,7 +1,7 @@
 use std::error::Error;
 use std::fmt::{Display, Formatter};
 use std::io::ErrorKind;
-use std::path::{Path, PathBuf};
+use std::path::{Component, Path, PathBuf};
 use log::debug;
 use sha1_smol::{Digest, Sha1};
 use tokio::fs::File;
@@ -110,3 +110,21 @@ pub async fn verify_file(path: impl AsRef<Path>, expect_size: Option<usize>, exp
     
     Ok(())
 }
+
+pub fn check_path(name: &str) -> Result<&Path, &'static str> {
+    let entry_path: &Path = Path::new(name);
+
+    let mut depth = 0usize;
+    for component in entry_path.components() {
+        depth = match component {
+            Component::Prefix(_) | Component::RootDir =>
+                return Err("root path component in entry"),
+            Component::ParentDir => depth.checked_sub(1)
+                .map_or_else(|| Err("entry path escapes"), |s| Ok(s))?,
+            Component::Normal(_) => depth + 1,
+            _ => depth
+        }
+    }
+
+    Ok(entry_path)
+}